A multimedia broadcast/multicast service (MBMS) transmits a multimedia contents packet obtained from a data source such as a contents provider (CP) or a multicast broadcast (MB) source server to a plurality of user equipments through a mobile communication network using a broadcasting scheme or a multicasting scheme.
In more detail, the contents providers interact with a broadcast and multicast service center (BM-SC) for managing and controlling MBMS. The BM-SC interacts with a gateway general packet radio service (GPRS) supporting node (GGSN) in order to transmit multimedia contents through a mobile communication network.
Since such a point-to-multipoint service transmits MBMS contents from a CP or a MB source server at once using a broadcast channel or a multicast channel which is shared by a plurality of user equipments, mobile communication network resources can be saved.
The MBMS is mainly used in the wireless communication network systems of a wideband code division multiple access (WCDMA) network and a European mobile phone, for example a GSM equipment. The MBMS simultaneously transmits contents to a plurality of equipments using a packet core network for providing a typical packet service with a BM-SC as a center and a bearer provided from a UMTS terrestrial radio access network (UTRAN). Herein, the BM-SC is a network element defined to manage the MBMS.
In order to provide a MBMS in a mobile communication network, a user equipment must have information about available services according to corresponding service areas. The BM-SC must perform service announcement to user equipments to enable the user equipments to receive information about a list of available multicast services and related services. The user equipments set an environment and provide the list of available services to a user using the received information, thereby allowing a user to select a desired MBMS.
In the mobile communication environment, the service announcement can be performed using a MBMS broadcast bearer or a MBMS multicast bearer. Also, the service announcement can be performed using service frame works provided from a mobile communication network such as a multimedia messaging service (MMS), a short message service (SMS), a call broadcast service (CBS), and a wireless application protocol (WAP). Furthermore, the service announcement may be performed using a service method used for transmitting a document between a web service and a client browser in a wired Internet network.
However, the above conventional methods excepting CBS use a unicast mode communication scheme. It is very ineffective to use a unicast channel to obtain service information in an environment where all of equipments must receive identical information in a corresponding area.
Therefore, it is reasonable to use a MBMS bearer to enable equipments to receive same information at the same time with one time data transmission.
Meanwhile, when a broadcast bearer is used, a MB-SC transfers service information to a mobile communication network using a broadcast mode. Since the mobile communication network transfers the service information to all of equipments through a broadcast channel available to all areas, all of equipments receive the same information.
Therefore, a user equipment receives all of service information including information about services not available at corresponding area. Then, the user equipment summarizes the received information only with available services at the corresponding area and provided the summarized information to a user. Since such a service announcement procedure is performed regularly, unnecessary information is regularly transmitted to the user equipment through a wireless resource, thereby wasting wireless resources.
That is, since the service announcement regularly transmit service information, the limited wireless resources are wasted to transfer information about services not available at a corresponding area. It may degrade the quality of a real MBMS. Therefore, it is preferable to reduce the amount of data transmitted through a wireless region by transmitting information of available services only according to a corresponding service area, thereby enabling a user equipment to use the announced information without additional processing.
The MBMS service announcement transfers different service lists and service information about contents transferred by a corresponding service according to a service area. However, if a broadcast bearer is used, all of equipments receive service information through only one broadcast channel although the equipments are located at different areas. Therefore, the BM-SC must use a corresponding broadcast channel to transmit information about the MBMS lists and contents transferred by each service. It requires an equipment to perform an additional process such as selecting services available at own area, and unnecessary information is transferred through a wireless resources.
In order to overcome the problems of the conventional method using the broadcast bearer, there is a demand for a service announcement method for selectively announcing services available according to a service area if services received according to geometrical areas are different.
Meanwhile, a MBMS multicast channel for service announcement is allocated to each of unit areas, and a BM-SC manages information to be provided to an equipment through service announcement according to unit areas, thereby providing only corresponding information to related areas. Such a procedure requires a MBMS multicast bearer setting step for service announcement. This procedure occurs when an equipment receives an Internet group management protocol (IGMP) or a multicast listener discovery (MLD) for IPv6 to register to a MBMS multicast service group.
However, since the service announcement must be always available regardless of the intention of equipment to receive service announcement, an IGMP or a MLD cannot be expected from the user equipment.